As known in the art, surgical fastener devices have long been employed in a wide variety of medical procedures. Simple filament sutures (stitches), for example, are perhaps the most common type of anchoring device utilized to hold one segment of tissue to another. Recently, to avoid the time required to sew up a wound and tie the sutures, rapid fastening procedures have been developed, wherein an "H" or "T"-shaped fastener is inserted into the tissue about the wound in lieu of a sewn stitch to hold the tissue segments together.
In 1977, Kronenthal et al. received a patent (U.S. Pat. No. 4,006,747) on a surgical fastening method which involves the partial insertion of "H"-shaped fasteners through the tissue adjacent an incision using a hollow needle and a push-rod. Once in place, an end of the fastener is located on each side of the incision, with a connecting filament spanning the incision between the two ends of the fastener. The fastener maintains the tissue in place thereby facilitating the natural healing process.
The "H"-shaped fastener is also utilized in a number of non-medically related fastening systems. This type of fastener is commonly used in stores to affix price tickets to clothing. A number of devices have been employed to install the fasteners in clothing. Two patents, U.S. Pat. Nos. 3,103,666 and 3,910,281, have been issued to A. R. Bone for hand held devices that aid in the insertion of this type of fastener into clothing.
In recent years, a modification of the fastening system has become prevalent in surgical procedures. Ogiu et al. (U.S. Pat. No. 4,235,238), teaches a system wherein a needle for inserting a "T" shaped fastener is located within the end of an endoscope. Ogiu makes use of a hollow needle that has a longitudinally extending cavity sized to receive the head of the fastener. Once the needle has passed through the tissue on both sides of the wound, an obturator is pushed through the interior of the needle to dislodge the head of the fastener. The needle is then removed and an outer filament end of the fastener is tied to a lock member to maintain the closure of the wound.
Richards et al. (U.S. Pat. No. 4,669,474) illustrates a similar system that makes use of a "T" shaped fastener. Richards implants the head of the fastener into the tissue of a patient using a hollow needle and push-rod (obturator). The head of the fastener is shaped so that it strongly anchors itself to the tissue, therefore providing a secure fastening point within the body. The filament end of the fastener is then externally secured to the skin using a shaped retainer.
Mueller et al. (U.S. Pat. No. 4,705,040) teaches a system that uses a "T" shaped fastener to anchor a hollow organ to the skin. In Mueller, a hollow needle and obturator are again used to implant the head of the fastener. However, Mueller places the head of the fastener within the interior cavity of the organ to be anchored. Mueller then utilizes a movable lock member to secure the outer filament end of the fastener to the exterior of the skin.
The above prior art summaries are merely representative of portions of the inventions disclosed in each reference. In no instance should these summaries substitute for a thorough reading of each individual reference.
Presently available systems and methods for inserting and placing "T"-shaped or "H"-shaped fasteners suffer from a number of serious deficiencies. Firstly, as the inner obturator is pushed in a forward direction through the hollow outer needle to eject the fastener, the operator must push on the obturator along its longitudinal axis while simultaneously attempting to hold the needle stationary. Since the direction of this forwardly directed force is also along the longitudinal axis of the hollow outer needle, and the inner obturator is operationally coupled within the needle, it is extremely difficult to eject the fastener without displacing the outer hollow needle beyond its desired operational orientation. In a medical application, any unnecessary forward displacement of the outer hollow needle may produce unwanted, deleterious tissue damage, potentially increasing the duration of the healing process and/or increasing the risk of postoperative infection. Secondly, since it is generally easy to overcompensate for this forward force, an operator may accidentally pull the needle slightly outwards during the fastener ejection process, possibly resulting in the improper positioning of the fastener within the patient. Thirdly, the outer needle generally incorporates a stop mechanism for limiting the forward displacement of the enclosed obturator. If any difficulties occur during the insertion process, or if the fastener insertion system is inadvertently damaged before, during or after bodily insertion, the stop mechanism could, perhaps, be rendered inoperable or ineffective, thereby permitting the obturator to travel beyond the desired insertion location. As such, needless tissue damage may be inflicted by the unconstrained obturator. Unfortunately, such deficiencies combine to reduce the effectiveness and convenience of currently available "H"-shaped or "T"-shaped fasteners.